1. Field of the Invention
The present invention relates to an electric blind installed at a window, and more particularly to an electric blind, which is designed to be automatically extended and folded and to be controlled in a tilt angle of vanes thereof, by remote control.
2. Description of the Prior Art
In general, windows of dwellings, offices and the like are equipped with curtains or blinds to assure security for a dweller"" privacy, as well as for natural lighting and thermal insulation, which are adapted to be expanded or retracted as necessary.
Blinds used in such applications are usually classified into a vertical-type blind and a horizontal-type blind. Both types are commonly constructed to control an amount of light incoming therethrough by adjusting a tilt angle of vanes thereof, but designs diverge, in that there is a difference in the direction of extension and folding of the vanes in the two types.
In conventional manual type blinds, since a user must go to the blind and then pull on a desired string in order to raise or lower the blind or control the tilt angle of its vanes, it is inconvenient to use.
To solve these problems, various electric blinds, which are electrically operated by remote control, are proposed these days. Since such a conventional electric blind has to be equipped with a motor for raising and lowering the blind and a motor for controlling the tilt angle of blind""s vanes of the blind, there are problems in that the number of overall components, and thus production cost, is increased.
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an electric blind, which can be electrically and easily raised and lowered, and which enables easy and stable control of tilt angle of its vanes, by manipulation of a remote control.
Another object of the present invention is to provide an electric blind, which enables simplification of components for controlling a tilt angle of vanes and is lower in the number of the components, thereby improving productivity and maintenance of the blind.
In order to accomplish the above object, the present invention provides an electric blind comprising: a mount frame fixedly mounted on a wall over a window and having a certain length; a pair of housings attached to both ends of the mount frame; a pair of take-up cylinders rotably coupled to the housings; lifting cords wound around the pair of take-up cylinders and unwound therefrom to be suspended by a certain length; a rotating pipe disposed between and joined to the pair of take-up cylinders and rotated in normal and reverse directions; a drive motor connected to the rotating pipe; a plurality of vanes disposed below the pair of housings to be raised and lowered by the lifting cords; and means for controlling tilt angle of the vanes via a turning force of the rotating pipe.
Each of the take-up cylinders may be provided at its outer surface with a threaded portion and provided at its inner surface with at least one fitting protrusion, and each of the housings may be provided at its inner surfaces with a threaded portion to mate with the threaded portion of the take-up cylinder and the rotating pipe may be provided at its outer surface with a fitting groove corresponding to the fitting protrusion, whereby the pair of take-up cylinders are moved toward and away from each other during rotation of the rotating pipe.
The means for controlling tilt angle of the vanes may comprise a rotating shaft axially joined to an end of the rotating pipe, a first rotating cam rotatably coupled to an end of the rotating shaft, a second rotating cam rotatably supported below the first rotating cam and connected to the uppermost vane of the plurality of vanes, a connecting link connected at its both ends to the first rotating cam and the second rotating cam, and means for limiting rotation angle of the first rotating cam.
The means for limiting the rotation angle of the first rotating cam may comprise a pair of protrusions fixed to the first rotating cam to be positioned at diametrically opposing sides, catch members provided at the rotating shaft and coming into contact with the protrusions of the first rotating cam to transmit turning force of the rotating shaft to the first rotating cam, and a stopper fixed to the housing to limit a rotation range of the protrusions of the first rotating cam.
The means for controlling the tilt angle of the vanes may comprise a rotating ring fixedly mounted on the rotating pipe, a tilting string wound around an outer surface of the rotating ring and having ends connected to both sides of the uppermost vane of the plurality of vanes, and a spacer provided at an end of the tilting string facing the window to maintain a certain spacing between the uppermost vane and the rotating ring.
The spacer may be comprised of a plurality of balls, through which the end of the tilting string passes.
The mount frame may be provided at its center with a control screw adapted to be displaced upward and downward, and a control wire connected at its one end to the control screw and connected at its other end to the uppermost vane of the plurality of vanes.
The electric blind may further include a holding bracket for fixing the mount frame to the wall, which includes bracket body having an end opening downward to receive the mount frame, and a bottom plate coupled the open end of the bracket body to support the mount frame.
The bracket body may be formed at its one end with a first slit and formed at its other end with a retaining protrusion, and wherein the bottom plate may be formed at its one end with a second slit to engage with the first slit of the bracket body, and formed at its other end with a cut portion to engage with the retaining protrusion of the bracket body.